1. Technical Field
The present invention relates to a projector.
2. Related Art
There has been known a projector that includes: a light source device, an optical modulator that modulates a light beam irradiated from the light source device in accordance with image information to form image light; and a projection optical device that projects the image light in an enlarged manner.
As the light source device of such a projector, an electrical-discharge light source device is often used, which includes: a light source lamp having a pair of electrodes between which light is generated by an electrical discharge; and a reflector that reflects a light beam emitted from the light source lamp in manner aligned in a predetermined direction. In the light source device, heat generated in light emission causes temperature rise in the light source lamp, generating thermal convection that causes temperature difference between an upper side and an lower side of the light source lamp. When difference in temperature distribution of the light source lamp is relatively large, blackening and the like are likely to occur on a lamp wall of the light source lamp, thereby causing brightness reduction or bursting of the light source lamp.
Accordingly, in order to reduce the temperature difference between the upper side and the lower side of the light source lamp to efficiently cool the light source lamp, a technique in which cooling fans are used to deliver air to the light source lamp substantially horizontally from a lateral side of the light source lamp has been suggested (see, for example, JP-A-2002-23261).
A technique disclosed in JP-A-2002-23261 is designed on condition that a projector projects image light substantially horizontally in a so-called normal posture in which the projector is set on a desk surface or the like and in a so-called suspended posture in which the projector is suspended from a ceiling upside down relative to the normal posture. In the projector projecting image light in either the normal posture or the suspended posture, air is supplied to the light source lamp in a horizontal direction to reduce the temperature difference between the upper and lower sides of the light source lamp, thereby efficiently cooling the light source lamp.
However, according to the technique disclosed in JP-A-2002-23261, when the projector projects image light in a posture to project image light substantially vertically (up and down direction), i.e. when the projector is in an upward-projecting posture (in which the projector projects image light upward) or in a downward-projecting posture (in which the projector projects image light downward), the cooling fans are located on an upper side or on a lower side of the light source lamp, so that the cooling fans can deliver the air only in a vertical direction relative to the light source lamp. For instance, when the cooling fans deliver the air toward the light source lamp from the lower side to the upper side, the lower side of the light source lamp is mainly cooled, so that the temperature difference is caused between the upper side and the lower side of the light source lamp. Hence, the light source lamp cannot be efficiently cooled.